927Z6SC - Differential Toxicity of Beryllium Materials

Principal Investigator (PI)

Primary Goal Addressed

Secondary Goal Addressed

None

Attributed to Manufacturing

100%

Project Description

Short Summary

The primary objective of this proposed research is to validate a transgenic mouse model for CBD. A major objective is to make the validated transgenic mouse available to the research community. The proposed research then applies this tool to important exposure questions and questions of genetic susceptibility. It will examine differential toxicities of various beryllium materials (metal, beryllium oxide, beryllium alloy and beryllium salts). It will examine different dose levels. It will examine route of exposure (skin versus lung) for beryllium sensitization. Different HLA-DPB1 transgenes (HLA-DPB1*0401 - resistant, HLA-DPB1*0201 - sensitive, and HLA-DPB1*1701 highly sensitive) will be tested for degree of sensitivity. Preliminary data strongly suggest that this model will make important contributions to understanding the mechanisms of CBD, thus, reducing respiratory disease in the manufacturing sector.

Description

The primary objective of this proposed research is to validate a transgenic mouse model for CBD. The mouse model comprises three strains of animal that were developed in collaboration with Dr. Eddy Rubin (Lawrence Berkeley National Laboratories, Berkeley, CA). The three model transgenes are: a mouse strain that is hemizygous for HLA-DPB1*0401, which is resistant to CBD, a mouse strain that is hemizygous for HLA-DPB1*1701, which is highly susceptible to CBD, and a mouse strain that is hemizygous for HLA-DPB1*0201, which is of intermediate susceptibility. Preliminary data strongly supports the success of this validation. A major objective is to make the validated transgenic mouse available to the research community.

There are four hypotheses: 1) different physicochemical forms of beryllium present quantitatively different risk of beryllium disease, 2) beryllium sensitization can occur through the skin, as well as the inhalation route, 3) different HLA-DPB1*E69 alleles (that code for the Glu69 marker that is associated with CBD) carry quantitatively different levels of CBD risk, and homozygotes are at higher risk than heterozygotes.

This study uses a posterior pharyngeal aspiration method of dosing mice that was validated in the laboratory of Dr. Ann Hubbs. Mice will be dosed with different forms of beryllium, over a range of doses and via the skin and pharynx. Genetic differences will be compared between the different strains. Pathology will be determined for the severity and dissemination of granulomatous inflammation and granulomata.

This proposed research is multidisciplinary, it requires: immunology expertise, epidemiology expertise, genetic expertise, pathology expertise, industrial hygiene expertise, and computational chemistry expertise. It cannot be done without interdivisional collaboration. The research program in which this proposed research has been developed has already produced multiple research reports that have been published in the peer–reviewed literature. It is reasonable to assume that several important publications will result.

The time-frame for this project is four years. It is expected that the validation will be completed by year two. In years two and three the comparisons of the different beryllium materials will be made. The comparisons of specific genotypes will be made in year four. The dosing of mice with beryllium materials will be performed under contract because one of the NIOSH investigators involved in the collaboration with Dr. Eddy Rubin to develop the mice (Dr. Sally Tinkle), who was going to prove and validate the phenotype, left NIOSH and now works at NIH. She subsequently developed collaborations with Dr. Terry Gordon, NYU, Tuxedo, NY, where the mice are now housed. Dr. Gordon was awarded the contract for the first year of the project (212-2007-M-20091) on March 12, 2007. That contract has been extended until May 31, 2009 due to the loss of one of the strains of mice (the ones with the HLA-DPB1*1701gene) and the initial low reproductive performance of the re-established strain. A contract and Justification for Other Than Full and Open Competition have been written for the second year of the project.

Objectives

The specific aims of Differential Toxicity of Beryllium Materials are:

2) to examine the granulomatous response in the lungs of transgenic mice treated with particles of beryllium metal, beryllium oxide, and beryllium sulfate;

3) to determine the relative contribution of the dermal versus pulmonary routes of exposure to the development of beryllium sensitization in the transgenic mouse model;

4) to evaluate the above observed environmental effects in the context of three distinct HLA genotypes: HLA-DPB1*0401 (CBD resistant), HLA-DPB1*0201 (CBD sensitive), and HLA-DPB1*1701 (CBD highly sensitive), and to assess the contribution of homozygosity and heterozygosity.

These aims contribute to our goal of providing an animal model for beryllium sensitization and disease to the research community. With this tool, research on metal sensitivity and associated granulomatous disease can help solve many questions about risk in metal industries. This project will test the following hypotheses:

a) different physicochemical forms of beryllium present quantitatively different risk of CBD,

b) beryllium sensitization can occur through the skin, as well as the inhalation route,

c) different HLA-DPB1*E69 alleles (that code for the Glu69 marker that is associated with CBD) carry quantitatively different levels of risk, and

d) homozygotes are at higher risk of sensitization and CBD than heterozygotes.

If successful the project should result in:

1) One publication/year submitted to peer-reviewed journals

2) One presentation/year at professional meetings

3) One meeting/year with stakeholders, e.g., the Program Leadership Team meeting with Brush Wellman workers, management, and researchers.

The success of the scientific productivity will be evaluated by collecting information on the use of the publications as documented by citations searches.

Mission Relevance

Surveillance data estimates 134,000 US workers are currently employed in industries that exposed them to beryllium. Once exposed to beryllium, the risk of Chronic Beryllium Disease (CBD) may be elevated for life.

Molecular epidemiologic studies suggest that some people are more sensitive to beryllium exposure than others. In addition, the bioavailability characteristics of different forms of beryllium suggest that exposure to some forms of beryllium are more likely to cause CBD than others. Further, the dose and route of exposure may influence the development of beryllium sensitization and CBD. A transgenic mouse model containing high, medium, and low risk human alleles for CBD was developed in collaboration with Dr. Eddy Rubin (Lawrence Berkeley National Laboratories, Berkeley, CA).

This project first validates this transgenic mouse model of CBD. Then, the project uses this model to experimentally define relative risks of CBD for soluble beryllium salts, beryllium metal, and beryllium oxide aerosols, so that these empirically determined risks can be compared to differential risks observed in the beryllium worker population identified in other projects within the beryllium program. The project also evaluates the skin and lung as routes for beryllium sensitization. Thus, this project complements other projects within the beryllium program because it provides laboratory comparisons of risks from different forms of beryllium and exposure routes in an animal model. At the completion of the project, this mouse model will be made available through the Jackson Laboratories (JAX Labs Inc., Bar Harbor, ME).

This proposed research will benefit workers by identifying: the most susceptible populations, the most hazardous exposure routes, and the most toxic forms of beryllium.

The surveillance information used in this project was taken from the NIOSH Beryllium Research Project.

This project supports the following goals: 1) Manufacturing Sector (100%) Goal 5: "Reduce the number of respiratory conditions and diseases due to exposures in the manufacturing sector"; and the Activity/Output Goal 5.2.8: "Perform epidemiologic and laboratory studies to elucidate mechanisms of beryllium-induced disease, including studies that clarify the role of genetic susceptibility in developing immunological sensitization to beryllium and chronic beryllium disease and the role of gene-environment interactions." 2) Respiratory Cross-Sector (100%) Goal 2: "Prevent and reduce work-related interstitial lung diseases". Intermediate Goal 2.4 (09PPRDRIG2.4) "Prevent and reduce beryllium sensitization and chronic beryllium disease" Activity/Output Goal 2.4.5 (09PPRDRAOG2.4.5) "Perform epidemiological and laboratory studies to elucidate mechanisms of beryllium-induced disease".